Systems that relied on pumping for pressure ended up under boil water advisories. Detroit, Cleveland, others. I think water pressure was mostly restored 3 or 4 days in though.
The tap water in Detroit never tasted the same afterwards, though no one else in my family felt the same way. I felt like I could taste and sometimes smell chlorine. Even the last time I visited Detroit (years later, and in a completely different part of the surrounding area).
The Detroit water system completely lost pressure. My assumption was that they upped the chlorine content to compensate for possible contamination in the system. They probably never reduced the concentration (either by design or by accident).
